The idea that the dwarf planet, which sits 270 million kilometers from Earth in the asteroid belt between Mars and Jupiter, holds water is more than 30 years old but has been hard to confirm. Now, astronomers report observations that Ceres releases water molecules from two distinct spots on its surface. The overall vapor loss is 6 kilograms per second and could come from ice changing directly to a gas or from ice volcanoes, the team writes in the Jan. 23 Nature.

Confirming Ceres has water also supports the idea that icy bodies, such as comets, may have migrated into the asteroid belt as the solar system was forming.